Improvement in electrical thermostatic alarms



UNITED STATES PATENT (DEEIoEo WILLIAM D. SNOW, OF BROOKLYN, NEIV YORK.

IMPROVEMENT IN ELECTRICAL THERMOSTATIC ALARMS.

Specification forming part of Letters Patent No. 155,208. dated September 22, 1874; application filed June 2, 1874.

To all lwhom it may concer/n:

Beit known that I, WILLIAM D. SNOW, of Brooklyn, in the State of New York, have invented a Portable Adjustable Electro-Magnetic Alarm-Thermometer; and I do hereby declare the following to be a full and correct description of the same, reference being had to the accompanying drawings, in which- Figure l is a front elevation of my alarmthermometer. mechanism for operating the bell.

The same letter indicates the same part wherever it occurs.

My invention consists in the application to aportable thermometer of an alarm-bell operated by theV closure of an electrical circuit derived from a battery concealed in the base or any convenient part of the mounting of the instrument, the circuit beiug normally open, but closed by the rising of the mercurial column to any predetermined degree of the scale, all as hereinafter more fully set forth.

In the drawing, Figure l represents one form of my alarm-thermometer, in which the Wires and other parts of the electrical apparatus are exposed to view in order more readily to illustrate the nature of the invention. In manufacturing this thermometer for the market, however, I contemplate concealing the operative mechanism, as far as possible, in the base and mountings of the instrument, so as to render it more ornamental and better protect the workin g parts from injury.

A marks the base of the instrument, which is surmonnted by the model of a castellated tower, B, having two lateral turrets, O C. On the face of the tower is placed the graduated plate, to which the glass bulb and stem of a mercurial thermometer are attached. This plate slides up and down in guides E E E E, and may be adjusted at any time to any position required. In the side turrets C C I locate the battery, which may be of any suitable kind. A dry battery is preferable. One pole ofthe battery is connected by the wire F with the mercury in the bulb G of the thermometer. The opposite poleis connected by wire H with the upper end of the thermometer, into which said Wire enters and descends to any desired degree of the scale at which it is predetermined that an alarm shall be sounded. The point on Fig. 2 is a side View of thethe scale to which said wire shall descend is regulated by sliding the plate D up or down in its guides. An outside index, It, corresponding in position with the end of Wire H, facilitates the adjustment of the plate. The electrical current includes the helices J K, which inclose the electro-magnet L. This magnet has an armature, M, attached to two yielding springs,N N, which react to hold the armature out of contact with the magnet. To the armature is attached the bell-hammer P, so adjusted that it will strike the bell Q. when the armature is drawn into contact with the magnet.

A second bell-hammer may be arranged in connection with the armature to strike the inside of the bell when the armature falls away from the magnet, thus signaling the breaking as well as the closure of the circuit.

The operation is as follows: The wire H is represented asA extending down the stem of the thermometer to the point on the scale marked 25C. The mercury in the stem stands at about 150. While this remains the case the circuit is open, and the armature M is not in contact with the poles of the electro-magnet. But when, by reason of increased temperature, the mercury in the stem rises to the point marked 250, it comes into contact with the end of wire H and closes the circuit, which causes the armature M to be drawn into contact With the electro-magnet L and an alarm to be sounded upon the bell Q by the hammer P. When the temperature falls below 250 the circuit is again broken and the armature is drawn away from the magnet by the spring-arms N N. A second hammer, attached to the armature, may be arranged to strike the bell when that fall of temperature occurs. A continuous alarm, if preferred, can be arranged to be operated by the closed current in any of the well-known methods. By sliding the plate D up or down the end of the wire H may be made to coincide with any desired point on the scale, and the alarm will be sounded when the temperature reaches that degree.

A thermometer thus constructed will afford a convenient means of calling attention to the temperature of any apartment in which it may be placed. While useful in every house, it will be found peculiarly adapted to the needs of the sick-room and hospital, and to conservatories and other places Where the nice regulation oi' the temperature is a matter of importance.

I do not confine myself to any particular' form of base and mountings, so long as the electric apparatus is so attached to them that the portability of the instrument is preserved.

I contemplate the use of any plain or ornamental mounting that I may prefer or iud adapted to the market.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is- 4 1. The sliding plate D, in combination With the thermometer-tube, the indicator R, and the Wire H, said wire forming part of an electric circuit operating au alarm, all constructed and arranged as described and shown, for the purpose specified.

2. As a new article of manufacture, an adjustable electro-magnetic alarm-thermometer, having a battery, circuit Wires, and alarmmechanism, mounted on a portable stand, all constructed and operating substantially as described.

The above specification of my said invention signed and witnessed at Washington this 27th day of May, A. D. 1874.

W. D. p SNOW.

Witnesses:

GEO. W. GOPELAND, CnAs. F. STANsBURY. 

